Beam Position Monitor System
Paper Title Page
MOCB02
 A Generic BPM Electronics Platform for European XFEL, SwissFEL and SLS  
 
  • B. Keil, R. Baldinger, R. Ditter, W. Koprek, R. Kramert, G. Marinkovic, M. Roggli, M. Stadler, D.M. Treyer
    PSI, Villigen, Switzerland
  
  Funding: Work supported by Swiss State Secretariat for Education and Research SER
PSI is currently developing the 2nd generation of a generic modular electronics platform for linac and storage ring BPMs and other beam diagnostics systems. The first platform, developed in 2004 and based on a generic digital back-end with Xilinx Virtex 2Pro FPGAs, is currently used at PSI for proton accelerator BPMs, resonant stripline BPMs at the SwissFEL test injector facility, and a number of other diagnostics and detector systems. The 2nd platform will be employed e.g. for European XFEL BPMs, a new SLS BPM system, and the SwissFEL BPM system. This paper gives an overview of the architecture, features and applications of the new platform, including interfaces to control, timing and feedback systems. Differences and synergies of the different BPM and non-BPM applications will be discussed. 		 
 
MOPA13 Real-time Calculation of Scale Factors of X-ray Beam Position Monitors during User Operation 1
 
  • C. Bloomer, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  
  Photoemission based X-ray Beam Position Monitors (XBPMs) are widely used at 3rd generation light sources to both monitor and stabilise the photon beam to sub-micron precision. Traditionally, finding the geometric scale factors requires either systematic stepper motor movements of the XBPM or well controlled electron beam displacements to measure the response of the XBPM. For each Insertion Device gap it is required to repeat this in order to build up a complete set of scale factors covering all possible operating conditions. Elliptically Polarising Undulators further complicate matters by having multiple operating modes which would require multi dimensional lookup tables. Presented in this paper is a method for retrieving the geometric scale factors of an XBPM in real time by making use of the intrinsic small random movements of the electron beam and finding the correlation in synchronous measurements from Electron BPMs and XBPMs at kHz sample rates.  
 
MOPA15 New Electronics Design for the European XFEL Re-entrant Cavity Monitor 1
 
  • C.S. Simon
    CEA/DSM/IRFU, France
  • N. Baboi
    DESY, Hamburg, Germany
  • R. Baldinger, B. Keil, R. Kramert, G. Marinkovic, M. Roggli, M. Stadler
    PSI, Villigen, Switzerland
  
  About one third of the beam position monitors (BPMs) in the European XFEL (E-XFEL) cryomodules will be re-entrant cavities. The BPM mechanics and Radio-Frequency front-end (RFFE) electronics are developed by CEA/Saclay. Two RFFEs and a digital back-end with two ADC mezzanines are integrated into a compact standalone unit called MBU (modular BPM unit) developed by PSI. The signal processing uses hybrids and a single stage downconversion to generate the signals sum and delta. Every RF/analog component of the re-entrant BPM electronics has been simulated with a Mathcad model and tested independently on test benches. The very low Q of the cavity monopole mode allows the new electronics to filter this mode at the dipole mode frequency and an IQ demodulation for delta and sum channels allow the digital back-end to determine the sign of the beam position just by comparing the phases of the channels, independently of beam arrival time jitter and external reference clock phase. This paper describes the design and architecture of a new re-entrant BPM electronics, including results of beam tests at FLASH that were performed to validate the chosen design.  
 
MOPA16 Design and Characterization of a Prototype Stripline Beam Position Monitor for the CLIC Drive Beam 1
 
  • A. Benot-Morell, L. Søby, M. Wendt
    CERN, Geneva, Switzerland
  • A. Benot-Morell
    IFIC, Valencia, Spain
  • J.M. Nappa, J. Tassan-Viol, S. Vilalte
    IN2P3-LAPP, Annecy-le-Vieux, France
  • S.R. Smith
    SLAC, Menlo Park, California, USA
  
  Funding: FPA2010-21456-C02-01, SEIC-2010-00028
The prototype of a stripline Beam Position Monitor (BPM) with its associated readout electronics is under development at CERN, in collaboration with SLAC, LAPP and IFIC. The anticipated position resolution and accuracy are expected to be below 2μm and 20μm respectively for operation of the BPM in the CLIC drive beam (DB) linac. This paper describes the particular CLIC DB conditions with respect to the beam position monitoring, presents the measurement concept, and summarizes electromagnetic simulations and RF measurements performed on the prototype. 		 
 
MOPA17 Modular Logarithmic Amplifier Beam Position Monitor Readout System at the University of Hawai'i 1
 
  • B.T. Jacobson, M.R. Hadmack, J. Madey, P. Niknejadi
    University of Hawaii, Honolulu, HI, USA
  
  High brightness electron beams for inverse Compton backscatter photon sources driven by thermionic microwave guns require real-time position measurements in order to achieve the spatial and temporal coincidence necessary to ensure statistically measurable signals. True logarithmic amplifiers are more adequately suited to signal comparison than are σ-delta methods. A low-cost, modular and scalable readout and data acquisition system for strip-line beam position monitors utilizing the AD640 log-amp is being developed at University of Hawai'i MkV Linear Accelerator and Free Electron Laser Lab. Initial measurements and prototyping of the hardware is complete with commissioning and deployment of the system currently ongoing. We present the methodology and early results of this project.  
 
MOPA18 A Prototype Cavity Beam Position Monitor for the CLIC Main Beam 1
 
  • F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • D. Bastard, E. Calvo, N. Chritin, F. Guillot-Vignot, T. Lefèvre, L. Søby, M. Wendt
    CERN, Geneva, Switzerland
  • A. Lunin, V.P. Yakovlev
    Fermilab, Batavia, USA
  • S.R. Smith
    SLAC, Menlo Park, California, USA
  
  The Compact Linear Collider (CLIC) places unprecedented demands on its diagnostics systems. A large number of cavity beam position monitors (BPMs) throughout the main linac and beam delivery system must routinely perform with 50 nm spatial resolution. Multiple position measurements within a single 156~ns bunch train are also required. A prototype low-Q cavity beam position monitor has been designed and built to be tested on the CLIC Test Facility (CTF3) probe beam. This paper presents the latest measurements of the prototype cavity BPM and the design and simulation of the radio frequency (RF) signal processing electronics with regards to the final performance. Installation of the BPM in the CTF3 probe beamline is also discussed.  
 
MOPA20
 Octave Broadband EO-probe Laser Source for High Resolution 3D-EO Sampling  
 
  • K. Ogawa, H. Tomizawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Matsubara, Y. Okayasu
    JASRI/SPring-8, Hyogo, Japan
  
  We have been developing three dimensional bunch charge distribution (3D-BCD) monitor for FEL seeded with high-order harmonic (HH) pulse. 3D-BCD is based on EO-sampling technique with multiple EO crystal detectors in the manner of spectral decoding. Using this 3D-EO sampling technique, the positioning and timing of electron bunch is obtained in real-time with non-destructive measurement. For obtaining the high temporal resolution, an octave broadband probe laser with linear chirp rate of 1 fs/nm is required. We are developing an EO-probe laser pulse with ~10 μJ pulse energy and the bandwidth over 300 nm (FWHM). For meet these bandwidth and pulse energy, this EO-probe pulse is using a supercontinuum generated by photonic crystal fiber (PCF) and amplified with optical parametric amplification (OPA). Especially, for amplification with maintaining octave bandwidth, non-collinear OPA (NOPA) using BBO crystal and a pump source with a wavelength of 450 nm are adopted. The EO-probe pulse energy of 10 μJ provides for high S/N ratio to each detector and the bandwidth of 300 nm with 300 fs pulse duration allows the measurement for the 30 fs electron bunch duration (FWHM).  
 
MOPA21 Improvement of the SIAM Photon Source Storage Ring BPM System 1
 
  • S. Klinkhieo, S. Boonsuya, P. Klysubun, S. Krainara, P. Songsiriritthigul, P. Sudmuang, N. Suradet, S. Tesprasitte
    SLRI, Nakhon Ratchasima, Thailand
  • J.-R. Chen, H.P. Hsueh, Y.-H. Liu
    NSRRC, Hsinchu, Taiwan
  
  This report describes the improvement of the Beam Position Monitoring (BPM) systems for the 1.2 GeV storage ring of the Siam Photon Source (SPS). The systematic studies and investigations for improving the machine performance, and storage ring BPM system has been carried out in the last few years. Some major technical problems have been found and solved. The inefficiency and unreliability of the original BPM system were also identified. They are mainly caused due to the use of low quality signal and improper installation of cables. Detailed descriptions of the replacement with the higher quality (lower loss and better interference shielding) BPM cables and implementation of a separated cable trays for the BPM cables, as well as the work on BPM electronic board calibration will be described. The measurement results before and after the improvement of the BPM system will also be presented.  
 
MOPA22
 Beam Position Measurement System in the Injector of HLS II  
 
  • J.Y. Zou, J. Fang, W.B. Li, P. Lu, T.J. Ma, B.G. Sun, Y.L. Yang, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: Supported by the National Science Foundation of China (11175173, 11105141)
A beam position monitor(BPM) system is being installed to improve the beam position measurement of the injector at the upgrade project of Hefei Light Source (HLS II). The new BPM system is consists of 19 stripline BPMs and 19 Libera Brilliance Single Pass modules. The parameters and placement of the stripline BPMs were carefully designed. A clock distribution system was built. An EPICS-based control and display system has been developed, including a new record type to calculate the beam position by log-ratio method. The performance of the electronic system is presented based on the laboratory tests as well as real beam test at HLS linac using existing BPMs. 		 
 
MOPA23
 Measurement of X-Y Coupling at J-PARC MR  
 
  • K. Ohmi
    KEK, Ibaraki, Japan
  • S. Hatakeyama
    JAEA/J-PARC, Tokai-mura, Japan
  
  In high intensity proton ring, nonlinear accelerator elements and space charge force in the presence of x-y coupling induces skew resonances. Degradation of the beam performance, beam loss enlargement, is caused by the resonances. x-y coupling has been measured in whole ring of J-PARC MR. We discuss the measurement and the effect of x-y coupling in the beam performance.  
 
MOPA24 Photon Beam Position Monitor at SIAM Photon Source 1
 
  • P. Sudmuang, S. Boonsuya, S. Chaichuay, P. Klysubun, S. Krainara, H. Nakajima, S. Rugmai, N. Sumano, N. Suradet
    SLRI, Nakhon Ratchasima, Thailand
  
  Photon beam position monitors (PBPM) have been designed and installed in the beamline front-ends at Siam Photon Source (SPS). Up till now, these blade-type PBPMs have been successfully installed at three bending magnet and an insertion device (planar undulator) beamlines. Its performance has been tested and compared with that of the electron beam position monitor. The achieved resolution is found to be better than 3 μm. The obtained PBPM data proved to be extremely invaluable in the investigation of the sources of the observed beam positional fluctuation, and for compensation of the orbit perturbation caused by undulator gap change. In this paper, the details of the calibration procedure will be presented. Various factors affecting reading of the signal such as back scattering effect, choice of bias voltage, and temperature variation have been investigated and the results will be discussed herewith.  
 
MOPA26
 Performance and Upgrade of BPMs at the J-PARC MR  
 
  • T. Toyama, Y. Hashimoto
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • K. Hanamura
    MELCO SC, Tsukuba, Japan
  • S. Hatakeyama
    JAEA/J-PARC, Tokai-mura, Japan
  • M. Okada, M. Tejima
    KEK, Ibaraki, Japan
  
  Since recovery from the great earthquake 2011.3.11, proton beam, more than 1014 ppp, is accelerated up to 30 GeV at the J-PARC MR. The BPMs were originally designed with the external capacitors. The aim was to improve the position response in wider frequencies and to get an adequate output voltage at the design intensity, 4x1013 ppb. It was modified, however, not to have the capacitors. Therefore we have sufficient signal intensity from low intensity beams of the initial beam commissioning, but too large from the design intensity beam. The processing circuits (BPMC) have to accommodate those output signals from high intensity beams. We are adding the attenuator-LPFs just before the BPMC. This paper will describe these additional attenuator-LPFs. In connection with the MR collimator upgrade, some BPMs are re-allocated. This process is also reported.  
 
MOPA27
 The Progress in BPM Electronic System of CSNS RCS  
 
  • W. Lu, X.L. Guan, H.Y. Sheng, X.C. Tian, Y.B. Zhao
    IHEP, Bejing, People's Republic of China
  
  The Beam Position Monitor (BPM) system is designed for the Rapid Cycling Synchrotron (RCS) in China Spallation Neutron Source (CSNS) to acquire beam position. This article introduces the design and implementation of the BPM electronic system. In the BPM system, signal is generated by diagonally cut electrode with dynamic range of 75dB (5.8mv~32V) and frequency range of 1MHz to 2.4MHz. Signals from the four electrodes of one test point are processed and digitalized individually, and the position is calculated using ⊿/∑ method in FPGA. It is the key point of our design to receive signal with large dynamic range while keeping low noise figure. Analog circuit with much consideration is described, and the primary test result of the system is provided in the end of this article.  
 
MOPA28 Turn-by-turn BPM System using Coaxial Switches and ARM Microcontroller at UVSOR 1
 
  • T. Toyoda
    IMS, Okazaki, Japan
  • K. Hayashi, M. Katoh
    UVSOR, Okazaki, Japan
  
  A major upgrade of the electron storage ring at UVSOR (Institute for Molecular Science, Japan) started from April 2012. To assist the commissioning procedure, we have developed a turn-by-turn Beam Position Monitor (BPM) system which consists of a signal switching circuit, a digital oscilloscope and software. The storage ring has 24 BPMs, each of which consists of four electrodes. By using the signal switching circuit, we can select one BPM from eight BPM's. The four signals from the BPM are sent to a digital oscilloscope and are recorded. In the switching circuit, coaxial switches of SPDT (Single Pole Dual Throw) and SP4T type are used. To control coaxial switches, we adopted 'mbed', the ARM microcontroller development kit. The 'mbed' stores the control applications configured in the HTML file and JavaScript library which can handle multiple I/O ports. It responds as a HTTP server and the control application runs on a Web browser. By clicking buttons with a mouse, we can control the I/O ports of 'mbed' through JavaScript library and accordingly can control coaxial switches. In the presentation, we will report the detail of the developed BPM system and its performance.  
 
MOPA30 Application of EMMA BPMs to the ALICE Energy Recovery Linac 1
 
  • A. Kalinin, D. Angal-Kalinin, F. Jackson, J.K. Jones, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  The ALICE Energy Recovery Linac arc button pickups have been recently equipped with EMMA BPM electronics*. These bunch-by-bunch EPICS VME BPMs give information about charge and position, and its jitter, allowing estimates of the beam energy jitter in ALICE in different modes of operation. A Mathematica program is designed to monitor statistically individual bunches (spacing 61.54ns) as well the train as a whole (up to 1625 bunches), allowing the study of jitter and position stability of the beam through the arc. The ALICE arc has been designed to be isochronous, with the bunch compression achieved through a separate dedicated bunch compressor chicane. The arc incorporates two sextupoles for correcting non-linear longitudinal matrix terms and experimental evidence suggests that the off-centred beam in the sextupoles breaks the linear isochronicity. We present some beam measurement results collected in 2012 using these BPMs.
*A. Kalinin et al, MOPPR061, IPAC12 		 
 
MOPA31 Design and Fabrication of the Stripline BPM at ESS-Bilbao 1
 
  • S. Varnasseri, I. Arredondo, D. Belver, F.J. Bermejo, J. Feuchtwanger, N. Garmendia, P.J. González, L. Muguira
    ESS Bilbao, LEIOA, Spain
  • V. Etxebarria, J. Jugo, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  
  A Stripline type BPM is designed and fabricated at ESSB. In order to compare, in the future, the functionality and response of the previous BPM capacitive pick-ups design with stripline, a design for stripline BPM is proposed. The design is based on travelling wave electrodes principles to detect the transverse position of the beam in the vacuum chamber. In the design of stripline setup, it has been considered to keep the comparison conditions with pick-ups as similar as possible. The length of strip electrodes is 200 mm and the coverage angle is 0.952 rad. The structure is rotationally pi/2 symmetric and the alignment of electrodes are pi/4, 3pi/, 5pi/4 and 7pi/4. The design is optimized for a frequency of 352 MHz, however it can function on a wide range of frequencies out coming from the measurement results. Striplines in general have well defined behavior even for low beta and low intensity beams as well as functionality at low and high frequencies. A report on the design and characteristics measurement of Stripline will be presented. The characteristics like frequency range, electrodes insulation, electrode response, sensitivities to beam power and position will be presented.  
 
TUPA11 SSRF BPM System Optimization and Upgrade 1
 
  • Y.B. Yan, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
  • L.Y. Yu, W.M. Zhou
    SINAP, Shanghai, People's Republic of China
  
  The beam position monitor (BPM) system at SSRF was fully equipped with Libera Electrons. It have operated steadily for nearly five years. During the summer shutdown of 2012 more than 50 Libera Electrons were upgraded to Libera Brilliance which are used mainly for fast obit feedback system. The software of whole system is upgraded from 1.42 to 2.07. Some other hardware and software optimizations are carried out. After this upgrade, the stability and performance have been improved significantly. This paper introduces the details of the optimization and upgrade.  
 
TUPA12 A DBPM Calibration Method Implemented on FPGA 1
 
  • X.D. Sun, Y.B. Leng
    SINAP, Shanghai, People's Republic of China
  
  An calibration method on the four channels of DBPM is discussed . Using interpolation, the method is implemented on FPGA , which can handle the data on-line. The calibration algorithm is mono-channel dependent and is intended to solve the beam current dependence problem and increase resolution. Orientations of the method is presented. Basic design diagrams of the pipelined FPGA modules are listed and comparisons are made before and after the calibration  
 
TUPA13
 Design Status of Beam Position Monitors for ADS Injector II Proton LINAC  
 
  • Y. Zhang, X.C. Kang, M. Li, J.X. Wu, J. Zhang
    IMP, Lanzhou, People's Republic of China
  
  Beam Position Monitors (BPM) based on capacitive pick-ups are designed for Accelerator-Driven System (ADS) Injector II proton LINAC. This LINAC is aiming to produce a maximum design current of 15 mA at the 10 MeV energy with an operating frequency of 162.5 MHz. Non-interceptive BPM will be installed to measure the transverse beam position and beam phase in the vacuum chamber. Depending on the location, the response of the BPMs must be optimized for a beam with an energy range from 2.1 up to 10 MeV and an average current between 0.01 and 15 mA. Apart from the broadening of the electromagnetic field due to the low-beta beam, specific issues are affecting some of the BPMs: tiny space in the transport line between the RFQ and the cryomodule and the cryogenic temperature inside the cryomodule. For this reason two types of BPMs are being designed for each location (MEBT and cryomoudle). In this contribution, the present status of the design of each BPM will be presented, focusing on the electromagnetic response for low-beta beams.  
 
TUPA14
 Development of Cavity-type Beam Position Monitors with High Resolution for ATF2  
 
  • S.W. Jang, A. Heo, E.-S. Kim
    KNU, Deagu, Republic of Korea
  • Y. Honda, T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  • J.G. Hwang
    Kyungpook National University, Daegu, Republic of Korea
  
  We have developed a high resolution beam position monitors for ATF2 at KEK, which is an accelerator test facility for International Linear Collider(ILC). The main goals of ATF2 are achievement of 37nm beam size and 2nm beam position resolution for beam stabilization. For these goals, low-Q IP-BPM(Interaction Point Beam Position Monitor) with latency of 20 ns are being developed. In this paper, we will describe about design of Low-Q IP-BPM, the basics test results as RF test and BPM sensitivity test. An electronics for Low-Q IP-BPM will be also described.  
 
TUPA15 Beam Postion Monitor for Energy Recovery Linac 1
 
  • I. Pinayev
    BNL, Upton, Long Island, New York, USA
  
  Funding: This work is supported by US Department of Energy.
The energy recovery linacs have co-propagating beams in the same vacuum vessel. These beams can have different trajectories, which should be distinguished by beam position monitors (BPM). In this paper we present a concept of BPM utilizing the phase information for calculation individual position of each of the two beams (accelerating and decelerating). The practical realizations are presented and achievable accuracy is estimated. 		 
 
TUPA16 HOM Choice Study with Test Electronics for use as Beam Position Diagnostics in 3.9 GHz Accelerating Cavities in FLASH 1
 
  • N. Baboi, B. Lorbeer, P. Zhang
    DESY, Hamburg, Germany
  • N. Eddy, B.J. Fellenz, M. Wendt
    Fermilab, Batavia, USA
  
  Funding: Work supported in part by the European Commission within the Framework Programme 7, Grant Agreement 227579
Higher Order Modes (HOM) excited by the beam in the 3.9 GHz accelerating cavities in FLASH can be used for beam position diagnostics, as in a cavity beam position monitor. Previous studies of the modal choices within the complicated spectrum have revealed several options*: cavity modes with high coupling to the beam, and therefore with the potential for better position resolution, but which are propagating within all 4 cavities, and modes localized in the cavities or the beam pipes, which can give localized position information, but which provide worse resolution. For a better characterization of these options, test electronics has been built, which can down convert various frequencies between about 4 and 9 GHz to 70 MHz. The performance of various 20 MHz bands has been estimated. The best resolution of 20 μm was found for some propagating modes. Based on this study one band at ca. 5 GHz was chosen for high resolution position monitoring and a band at ca. 9 GHz for localized monitoring.
* N. Baboi et al., SRF2011, Chicago, IL, US 		 
 
TUPA17 TPS BPM Electronics Performance Measurement and Statistics 1
 
  • P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo
    NSRRC, Hsinchu, Taiwan
  
  The new BPM electronics Libera Brilliance Plus are developed for Taiwan Photon Source (TPS) which is a 3 GeV synchrotron light source constructed at NSRRC. This new BPM electronics can accommodate four BPM modules with integrated FPGA-based hardware. The preliminary test for the first arrival unit had been performed in the TLS (Taiwan Light Source) and had shown nearly equal performance compared with Libera Brilliance. The extra 75 sets had been delivered in 2011 and 2012. Performance of each unit are individually tested and measured.  
 
TUPA18 Development of the Beam Position Monitors for the SPIRAL2 Linac 1
 
  • M. Ben Abdillah, P. Ausset, G. Belot, P. Blache, P. Dambre, J. Lesrel, E. Marius
    IPN, Orsay, France
  
  Funding: CNRS (Centre National de la Recherche Scientifique) CEA (Commissariat à l'Energie Atomique); Région Basse Normandie Co-Authors: P. Ausset, J. Lesrel, P. Blache, P. Dambre, G. Belot, E. Marius
The SPIRAL 2 facility will be able to deliver stable heavy ion beams and deuteron beams at very high intensity, producing and accelerating light and heavy rare ion beams. The driver will accelerate between 0.15mA and 5 mA deuteron beam up to 20 MeV/u and also q/A=1/3 heavy ions up to 14.5 MeV/u. The accurate tuning of the LINAC is essential for the operation of SPIRAL2 and requires from the Beam Position Monitor (BPM) system the measurements of the beam transverse position, the phase of the beam with respect to the radiofrequency voltage and the beam energy. Twenty three BPM were realized for SPIRAL2. This paper addresses all aspects of the design, realization, and calibration of these BPM, while emphasizing the determination of the beam position and shape. The measurements on the BPM are carried out on a test bench in the laboratory: the position mapping with a resolution of 50 μm is performed and the sensitivity to the beam displacement is about 1.36dB/mm at the centre of the BPM. The characterization of the beam shape is performed by means of a special test bench configuration. An overview of the electronics under realization for the BPM of the SPIRAL2 Linac is given.
Keywords: BPM, SPIRAL2, position mapping , sensitivity
References:
*P. Ausset « Overview of the beam diagnostics for the driver of SPIRAL 2»
*R.H.Miller « Nonintercepting Emittance Monitor » 		 
 
TUPA19 First Tests of a Low Charge MTCA-based Electronics for Button and Strip-line BPM at FLASH 1
 
  • B. Lorbeer, N. Baboi, F. Schmidt-Föhre
    DESY, Hamburg, Germany
  
  Current FEL based light sources foresee operation with very short electron bunches. These can be obtained with charges of 100pC and lower. The specified charge range for FLASH, DESY, Hamburg goes from 100pC up to 1nC. The electronics currently installed at button and stripline BPMs of FLASH have been designed for best performance at higher charges and have reached their limits. Currently a new type of electronics is being developed at DESY to overcome these limitations. These electronics is/are conforming with the uTCA for physics standard(ref). This paper describes the next generation of FLASH BPM electronics suitable for button and stripline BPM. Furthermore the first measurement results taken with beam at FLASH, DESY are presented here.  
 
TUPA20
 Prototype Development of a Beam Position Monitor for Hadrontherapy Facilities and First Beam Test in the PS  
 
  • J.J. García-Garrigós, C. Belver-Aguilar, C. Blanch Gutierrez, A. Faus-Golfe
    IFIC, Valencia, Spain
  • M. Haguenauer, P. Poilleux
    LLR, Palaiseau, France
  
  Beam Position Monitors (BPM) are crucial to control the beam in Hadrontherapy accelerators, especially in the secondary transport lines towards the patient room where the beam position must be determined with high precision. In this paper we describe the design and construction of a first prototype based on four scintillating fibers coupled to one photodiode each, to detect the light produced by the fibers when intercepting the beam tails. The results of the first beam test using a 6GeV proton beam from the PS accelerator at CERN are also presented. This beam test, jointly with a previous calibration test done with a radioactive source, has been served to evaluate the different design options of the prototype and its read-out electronic setup in order to define the best processing method to get the beam position.  
 
TUPA22 Design of RF Front End for Cavity Beam Position Monitor based on ICs 1
 
  • B.P. Wang, Z.C. Chen, Y.B. Leng, L.Y. Yu, R.X. Yuan, W.M. Zhou
    SINAP, Shanghai, People's Republic of China
  
  RF front end has the significant impact on the performance of cavity beam position monitor (CBPM) which is indispensable beam instrumentation component in free electron laser(FEL) or linear collider facility. With many new advances in data converter and radio technology, complex RF front end design has been greatly simplified. Now based on digital intermediate frequency (IF) receiver architecture, a new RF front end for (CBPM) has been designed and fabricated using surface mount component on print circuit board (PCB). The front end contains analog-digital converter used to digitize the IF signals. The whole system would be integrated to a digital board developed by our lab to produce the dedicated signal processor for CBPM. There is an Xilinx Vertex-5 FPGA device on the digital board and relevant signal processing algorithm has been implemented on it using VHDL. The details about design and test results would be introduced blow.  
 
TUPA23 Performance of a Downconverter Test-electronics with MTCA-based Digitizers for Beam Position Monitoring in 3.9 GHz Accelerating Cavities 1
 
  • T. Wamsat, N. Baboi, B. Lorbeer
    DESY, Hamburg, Germany
  • P. Zhang
    UMAN, Manchester, United Kingdom
  
  Beam excited higher order modes (HOM) in 3.9GHz accelerating cavities at the European XFEL are planned to be used for beam position monitoring. The selected HOMs are located around 5440MHz and 9060MHz and are filtered in a bandwidth of 100MHz. A downconverter test electronics converts the HOMs to an intermediate frequency of 70MHz. The μTCA (Micro Telecommunications Computing Architecture) standard will be used for the XFEL. Thus it is important to have a performance study of the downconverter test electronics using the μTCA digitizer card SIS8300. In the digitizer IF frequency of 70MHz is undersampled with a clock frequency of 108MS/s. The paper will present the performance of the digitizer together with the test-electronics. A comparison with a 216MS/s VME (Versa Module Eurocard) digitizer will be made.  
 
TUPA24 Design of Cavity BPM Pickups for SwissFEL 1
 
  • F. Marcellini, B. Keil, M. Rohrer, M. Stadler, J. Stettler, D.M. Treyer
    PSI, Villigen, Switzerland
  • D. Lipka, D. Nölle, M. Pelzer, S. Vilcins
    DESY, Hamburg, Germany
  
  SwissFEL is a 0.1nm hard X-ray Free Electron Laser being built at PSI. A photocathode gun, S-band injector and C-band linac provide 2 bunches at 28ns spacing, 10-200pC charge, and 5.8GeV maximum energy. A fast distribution kicker will provide one bunch each to one hard X-ray and one soft X-ray undulator line. For linac and undulators, first prototypes of dual-resonator cavity BPM pickups have been designed and fabricated. The pickups were optimized for low charge and short bunch spacing in the linac. Design considerations, simulation and first test results will be reported.  
 
TUPA25 Signal Transmission Characteristics in Stripline-Type Beam Position Monitor 1
 
  • T. Suwada
    KEK, Ibaraki, Japan
  
  New stripline-type beam position monitor (BPM) system is under development at the KEKB injector linac in order to measure transverse beam positions with a high precision less than 10 micron meters towards the Super KEKB-factory (SKEKB) at KEK. During the KEKB operation, conventional stripline-type BPMs with a position resolution of 0.1 mm have been working well. However, the high-precision BPM system is strongly required for the SKEKB operation to stably accelerate single-bunch electron and positron beams with high bunch charges of ~5 nC/bunch, and also to keep the beam stability with higher brightness. The new stripline-type BPMs with large aperture compared with previously designed BPMs, which will be installed just after the positron production and capture section, have been designed. In this report, the basic design for fabricating the prototype stripline-type BPM, and, especially, theoretical analysis and experimental investigations on the signal propagation characteristics and performance along the stripling electrodes are described in detail on the base of a coupled-mode analysis of uniform coupled transmission lines.  
 
TUPA26 Development of New BPM Electronics for the Swiss Light Source 1
 
  • W. Koprek, R. Baldinger, R. Ditter, B. Keil, G. Marinkovic, M. Roggli, M. Stadler
    PSI, Villigen, Switzerland
  
  PSI is currently developing new BPM electronics for the Swiss Light Source (SLS). Although the present "DBPM1" system that was designed 12 years ago still allows to achieve excellent beam stability and uptime, the development of a new system is motivated by long-term maintenance, improved performance in line with increasing user requirements, and new features and functionality provided by latest electronics technology. The new electronics is based on a generic modular BPM electronics platform developed by PSI that will also be used for linac based FELs like European XFEL and SwissFEL. The hardware and firmware architecture of the present prototypes as well as first test results will be presented.  
 
TUPA27 Beam Test Results of Undulator Cavity BPM Electronics for the European XFEL 1
 
  • M. Stadler, R. Baldinger, R. Ditter, B. Keil, R. Kramert, G. Marinkovic, M. Roggli
    PSI, Villigen, Switzerland
  • D. Lipka, D. Nölle, M. Pelzer, S. Vilcins
    DESY, Hamburg, Germany
  
  Funding: Work supported by Swiss State Secretariat for Education and Research SER
The European X-ray Free Electron Laser (E-XFEL) will use dual-resonator cavity BPMs (CBPMs) in the SASE undulators to measure and stabilize the beam trajectory. The BPM electronics is developed by PSI, while the pickup mechanics is developed by DESY. First beam tests with three adjacent pickups have been performed. The system architecture and algorithms, achieved performance and noise correlation measurements of the present electronics prototypes will be presented. 		 
 
THTA01
 Beam Position Monitors for Circular Accelerators  
 
  • S. Hiramatsu
    KEK, Ibaraki, Japan
  
  The electrostatic induction type beam position monitors (BPMs) for circular accelerators such as proton synchrotrons and electron accumulation rings will be discussed. Discussions on the beam induced charge on the BPM pick-up electrodes, signal detection systems, and techniques of beam based alignment and beam based calibration will be given. For high beam current machines, the evaluation of the beam coupling impedance of BPM is an important issue to avoid the beam current limit by beam instabilities caused by BPM impedances. Another serious problem is the movement of BPMs by the thermal distortion of the beam pipe by high power synchrotron radiation. These problems will be also mentioned briefly.  
slides icon Slides THTA01 [6.252 MB]